Question

a)3/4+4/7=
b)5/2-1/6=
c)7/3-5/12=
d)3/8+7/12=
2) resolva as operações
a)4/12×6/16=
b)1/10×10/15=
c)3/5÷9/15=
d)3/20÷21/18=​

Answer 1

Resposta:

$\frac{3}{4} + \frac{4}{7} = \frac{(28 \div 4 \times 3) + (28 \div 7 \times 4)}{28} = \frac{21 + 16}{28} = \frac{37}{28}$

$\frac{5}{2} - \frac{1}{6} = \frac{(12 \div 2 \times 5) - (12 \div 6 \times 1)}{12} = \\ \frac{30 - 2}{12} = \frac{18}{12}$

$\frac{7}{3} - \frac{5}{12} = \frac{(12 \div 3 \times 7) - (12 \div 12 \times 5)}{12} \\ \frac{28 - 5}{12} = \frac{23}{12}$

$\frac{3}{8} + \frac{7}{12} = \frac{(24 \div 8 \times 3) + (24 \div 12 \times 7)}{24} \\ \frac{9 + 14}{24} = \frac{23}{24}$

Questão 2

$\frac{4}{12} \times \frac{6}{16} = \frac{4 \times 6}{ 12\times 16} = \frac{24}{192}$

$\frac{1}{10} \times \frac{10}{15} = \frac{1 \times 10}{10 \times 15} = \frac{10}{150}$

$\frac{3}{5} \div \frac{9}{15} = \frac{3}{5} \times \frac{15}{9} = \frac{3 \times 15}{5 \times 9} = \frac{45}{45} = 1$

$\frac{3}{20} \div \frac{21}{18} = \frac{3}{20} \times \frac{18}{21} = \frac{3 \times 18}{20 \times 21} = \frac{54}{420}$